Werner siemens



-UNITED STATES PATENT OFFICE.

\VERNER SIEMENS, OF BERLIN, GERMANY, ASSIGNOR TO SIEMENS & I'IALSKE, OF SAME PLACE.

I PROCESS OF MANUFACTURING INSULATED CONDUCTORS.

SPECIFICATION forming part of Letters Patent No. 395,083, dated December 25, 1888.

Application filed August 26, 1884. Serial No. 141,472. (No specimens.) Patented in Germany March 2, 1880, No. 12,178, and in Austria-Hungary May 17, 1880,1T0 9,574 and No. 2,525.

To aZZ whom it may concern:

Be it known that I, Dr. WERNER SIEMENS, a subject of the King of Prussia, German Emperor, and a resident of the city of Berlin, Prussia, Germany, have invented an Improved Process of Manufacturing Insulated Conductors, (for which I have obtained a patent in the German Empire, No. 12,178, bearing date March 2, 1880, and in Austria- Hungary, No. 9,574 and No. 2,525, bearing date May 17, 1880,) of which the following is'a specification.

This process is based upon the experience that cotton jute or similar vegetable fibers are perfectly insulated if they are com pletely freed from moisture and in that con dition impregnated with a liquid that prevents the resorption of water. As such a liquid, the oil obtained from caoutchouc by heating the latter has proven to be especially suitable, either alone or mixedwith resins or similar substances which combine with or dissolve in oil.

The process for the manufacture of insulated conductors consists in spinning cotton, jute, flax,hemp, and similar fibrous material, spun to threads over the wire or wire strand to be insulated, whereby, as a rule, warpthreads are laid around and the overspinning is repeated one or several times. The wire thus overspun is now put in an airtight vessel, and after closing it the air is as completely as possible removed by exhaustion or otherwise. In order that the hygroscopic water may be completely remox'ed from the fibrous material of the covering the vessel is brought into connection with another \"essel, likewise air-exhausted and partly filled with an intensely-conccntrated sulphuric acid or any other substance intensely water-absorbing; or these suliistances, together with the oyerspun wire, are put into the samevessel before it is closed or exhausted. At the same time the sides of the vessel are heated by steam or in some other manner. 'When after a time all the moisture removed from the overspun wire or strand, the vacuum, by opening a cock, is caused to suck into the vessel the above-mentioned heated liquid, so that the fibrous material becomes saturated with it before it comes in contact with the moist air. The covered wire is then taken out of the liquid, and the remainder of the latter is, by means of a cen trifuge, thrown off. The covered conduct ors in this manner prepared are 110w, in case several conductors are to be united to a strand, in a suitable manner-twisted together. If in order to avoid induction-currents double conductors are used, then two covered wires which, for instance, are to be used as telephone-conductors, are separately twisted togther, and then with other double wires or double-wire strands twisted into a With great-er lengths the tube is pressed directly around the strand or core by means of a hydraulic press, the strand or core passing through both the hydraulic and the metal cylinder inside of a steel protectiont-ube. For the protection of the now finished cable against external injuries, as well as against oxidation, the cable is covered 1 with compound jute or another fibrous stuff and then in the usual manner covered wit iron wires.

Having thus described my invention, I claim and desire to secure by Letters Patent The process of impregnating the fibrous matter covering a wire or strands of wire with caoutchouc, oil, or other similar liquid, which consists in drying the covered wires under vacuumby means of sulphuric acid or other hygroscopic substance, and then admitting the heated ca'oiitchouc, oil, or other substance into the vacuum-chamber containing the wire,- substantially as and for the puri i i l 

